img{
    margin: 0;
    padding: 0;
}
.fix::after{
    height: 0;
    content: " ";
    display: block;
    overflow: hidden;
    clear: both;
}
#screen{
    width: 375px;
    height: 667px;
    /* border: 1px solid #000; */
    overflow: hidden;
    position: relative;
    margin: 50px auto;
}
.bgbox{
    width: 100%;
    position: absolute;
    left: 0;
    bottom: 0;
}
.bgbox img{
    float: left;
}
.player{
    position: absolute;
    top: 75%;
    left: 50%;
    z-index: 2;
    width: 20%;
    height: 0;
    padding-bottom: 31%;
    background: url(../images/player.png) no-repeat;
    background-size: cover;
    margin-left: -10%;
    margin-top: -15%;
}
.bullet{
    width: 16px;
    height: 10px;
    background-color: rgb(172, 10, 64);
    z-index: 1;
    position: absolute;
    left: 50%;
    top: 75%;
    margin-left: -8px;
}
.enemy{
    width: 50px;
    height: 25px;
    background-color: red;
    position: absolute;
}